In St Paul's thought, it is by the painful Passion and death of Our Lord, and by the power of his Resurrection, that Christ has won dominance over our living and our dying.
So he takes us, even here on earth into himself, and takes our living and our dying into himself, giving them the value which came from his own dying and his living.
Here our living precedes our dying, but with him his dying preceded the glory of his resurrection into an eternal state for himself, communicated to all of those who are incorporated into himself on earth, as branches in the true vine.
A particular aspect of this reality is the object of Paul's reflections here. No one more than he was aware of that dominating force of the death and risen life of Christ being present in himself, so that our course is the complement of Christ's, the evident way of salvation for men.
Thanks to his death and resurrection we receive into our living bodies the immortal glorified human life of Christ, animated by himself as the Only-begotten Son of the Father, with whom and with the Holy Spirit he is equal in their unique divinity.
So to Paul, simply speaking, 'to live is Christ', in this life, and yet 'to die is gain', because he knows that he will enjoy that life with unassailable permanence after his death.
It might very well seem that any choice for him is already made. It points to choosing this eternal state. And yet he is already enjoying in the reality of his sanctified flesh a fruit which derives from the presence of the divine life in his own and in his activity from the moment of his conversion, and when, definitively with his baptism in Damascus, he was incorporated into that 'me' of Christ, which is His presence in His Church.
Not only is he in the spirit of that Body as identical with it in the fullest sense; he is also a teacher within the Church, a preacher of the truth of this reality -- demonstrating its beauty so that others will also be captivated by its beauty and its truth, and will want it for themselves, having identified their deepest longings with it which gives to every man an infinite completeness by this identity with the God of this God-Man, Jesus Christ.
Paul realised how important that apostolic office is, and he was as a living man no more at home on earth than in the company of other believers, who were learning to reflect back into himself, as their mediating source, the revelation which he had communicated to them.
And finally Paul discovers an expression for which he has been searching in his own soul which should satisfy the Philippians to whom the circumstances of his second Missionary Journey had brought him: in Greece, but with a Roman name. The selector of these readings had seen that a verse still to come makes up a conclusion, a point of union between them who wanted his presence, and he torn between wanting to be dissolved in Christ and wanting to remain with them, and so to be close to the fruit of his own preaching.
'Let your conversation' -- all of your social life together -- 'be worthy of the gospel of Christ', especially in your prayer, and in your prayer at its highest in the celebration of the Eucharistic mysteries which contain the whole mystery of Christ, in all of its infinite aspects.
That is external to both Paul and to the Philippians. In that they should find the highest repose. This is the essential Gospel as preached and experienced as the highest reality because it is divine, even before the individual Gospel books have been written and circulated. Therefore stay faithful to that reality which has been communicated to them by himself, something which is divine and to be served, and live in it.
And so, in words omitted as the end of the final verse only partially quoted:
whether I come to you and see for myself, or stay at a distance and only hear about you, that you stand together in one spirit and in one soul, striving together in the faith of the gospel.